What this means
The IEEE assigned the MA-L block 4CD4B1 to NXP Semiconductor (Tianjin) LTD.. Every network interface they manufacture under this block has a MAC address beginning with these digits, followed by a unique per-device identifier. If a device on your network shows a MAC starting 4C:D4:B1, it is NXP Semiconductor (Tianjin) LTD. hardware.